Reading and writing head mounting means



May 5, 1964 M. K. TAYLOR READING AND WRITING HEAD MOUNTING MEANS Filed Sept. 16, 1959 I 2b as OOOOOOOOOOOOOOOOOOOOP FIG. I

IN VE N 7' OR MAU/P/Cf KENYON MYLOR United States Patent 3,132,328 READING AND WRITING HEAD MOUNTING MEANS Maurice K. Taylor, Weston, Untario, Canada, assignor to Ferranti Packard Electric Limited, Toronto, Ontario, Canada Filed Sept. 16, 1959, Ser. No. 840,325 Claims priority, application Canada Sept. 19, 1958 8 Claims. (Cl. Mil-174.1)

This invention relates to a device for maintaining the distance between reading and/ or writing heads of a computer at a predetermined distance from the recording surface of the drum or the like in connection with which they operate.

The distance between the reading and/or writing heads of the computer and the recording surface of the drum upon which they operate, must be kept within fairly close limits for good operation. In the past, this has meant that the recording drums, which are relatively large, must be manufactured to very close tolerances if one is to be able to interchange recording drums on a machine.

I have devised a means for automatically maintaining the distance between the reading and/ or writing head of a computer and the recording surface upon which it operates proper for any drum fitted to a given machine.

With my invention it is not necessary to manufacture the drums to such close tolerances as before, since adjustment for variations will automatically be made.

Generally speaking, I mount the reading and/ or writing head on a carrier that is adjustably mounted with respect to the base and that supports the heads in various degrees of proximity to the recording surfaces of the drum. A pneumatic control means, including a nozzle that is adapted in use to discharge against a drum surface, exerts a force on the carrier, tending to urge it away from the drum'and against a compensating means that exerts a force on the carrier towards the drum. The pressure in the control means is a function of the distance between the nozzle and the recording surface of the drum and the control means responds to changes in this pressure to keep the carrier a constant distance from the drum. If, for example, the distance between the discharge end of the nozzle and the recording surface of the drum should increase, the pressure within the nozzle would drop due to the more free escape of air therefrom and the compensating means would urge the carrier together with the nozzle which is mounted on it towards the drum. This would reduce the distance between the nozzle and the drum with a resulting increase of pressure within the nozzle that would cause the control means to move the nozzle away from the drum again. Balance between the control means and the compensating means is achieved when the nozzle, and the carrier upon which it is mounted, are a predetermined distance from the drum. The invention will be clearly understood after reference to the following detailed specification read in conjunction with the drawings.

In the drawings,

FIGURE 1 is a front view of a nozzle adjusting means according to this invention, and

FIGURE 2 is a plan view of FIGURE 1.

The computer to which this invention has been applied is not illustrated in detail. It is, however, a computer of the type referred to in Canadian Patent No. 598,482, issued on May 24, 1960. It has a recording drum, a portion of the cylindrical recording surface of which is indi cated by the numeral 10 and one or more reading and/ or writing heads 12, mounted in proximity to the recording surface 10 of the drum. The numeral 14 indicates the input to the reading and/or writing heads 12.

The reading and/ or writing heads 12 are mounted in a vertically extending series on the panel 16 of the carrier "Ice 18 which is in turn, adjustably mounted with respect to a base 20 by means of the flexible strips 22 whereby the carrier is adjustable with respect to the base 20 to support the reading and/ or writing heads 12 in various degrees of proximity to the recording surface ll) of the drum. The base 20 is bolted to the base of the computer within which storage drum It) is mounted so that, in effect, it becomes a portion of the base of the computer.

Thus by bolting the yieldable strips 22 to the post 24 of the base 28 as at 26, adjacent one of their ends and to the carrier by means of the bolt 28 adjacent their other ends, the carrier for the heads 12 is adjustably mounted as aforesaid.

Pneumatic control means including a control nozzle 30 and, in the embodiment illustrated, a bellows 32 that connects with the central standard 34 of the base at one of its ends and with the carrier 18 at the other of its ends, is provided and in use it operates against a compensating means, which in the embodiment of the invention illustrated, comprises a bellows 36 that connects at one of its ends with the standard 34 of the base and at the other of its ends with the carrier 18.

The device is pneumatically operated and means are provided for supplying air or the like to the pneumatic control means and compensating means.

There is a nozzle 30, similar to the one shown in FIG- URE 2, at each extremity of the carrier 18 each of which are mounted on the carrier to discharge against the surface of the drum 10 so that, as will be explained later, the pressure in the nozzle is a function of the distance between the nozzle and the drum surface.

Air for the nozzle and the control bellows 32 is supplied from the line 49, through the restriction of the needle valves 42, through the tubes 44, and the tubes 46. It will be noted that the interior of the bellows 32 communicates with the tube 46 through the tube 48.

Air is supplied to the compensating bellows 36 through the supply tube 40, the restriction of the needle valves 50 and the tubes 52.

In use, air is supplied through the tube 40 to the bellows 32 and the nozzle 30. It discharges from the nozzles 30 against the drum 10 to cause a build-up of pressure in the bellows 32 that is a function of the distance between the discharge end of the nozzle 30 and the drum surface It). If, for example, the distance is small, the pressure build-up in the bellows 32 will tend to be relatively great. If the distance is increased, the pressure build-up in the bellows 32 will not be reduced. Thus the bellows 32 at each end of the carrier 18, tend to expand and move the carrier away from the drum when the distance between the discharge end of the nozzle and the drum becomes small. They contract, as a result of forces of the compensating bellows 36 to be referred to later, when the pressure therein is reduced.

The force of the compensating bellows 36 is adjusted to be constant during operation and maintain the nozzles 30 a predetermined distance from the surface of the drum. It will be apparent that because of the leakage from the control nozzle the pressure in the control bellows will be substantially less than the pressure in the compensating bellows 36 since the pressure in the compensating bellows is line pressure. Thus the surfaces upon which the pressure in the compensating bellows 36 operate must be proportionately smaller than the surfaces on which the pressure in the control bellows 32 operate, in order that the two maybe in equilibrium with the nozzles at a predetermined distance from the recording head 10. The exterior of the bellows 36 has been illustrated as being of v,

the same size as the bellows 32. However, it will be appreciated that the operating areas are designed in ac cordance with the above.

As an alternative to providing smaller bellows operating surfaces in the bellows 36, one could have the operating surfaces of the bellows 36 and 32 of equal size, and provide for means for bleeding air from the bellows 36 to reduce the pressure therein to the normal build-up pres sure in the bellows 32, when the nozzles 30 are a required distance from the surface 10. It is only necessary that the force provided by the compensating bellows should balance the force built up in the control bellows when the nozzles 30 are a predetermined distance from the surface 10.

The restriction in the needle valves 42 should provide a relatively high impedance to the flow of air as compared to the impedance of the nozzle 30, so that the air flow to the control bellows is small.

It is desirable that there should be no build up of pressure in the control bellows if the nozzles 34) were permitted to discharge into open atmosphere not obstructed by the surface of the drum 1%.

With a pressure of 30 lbs. per square inch on the input line 40, a flow of .05 cubic foot per minute through the nozzles gives a build up pressure of about lbs. p.s.i. in the control bellows and a satisfactory result.

The restriction of the valves 59 serves to limit the fast build up of the compensating bellows with the resulting abrupt forward movement of the carrier when the air pressure is initially turned on.

It will be appreciated that means other than a pneumatically operated compensating device could be used.

The essence of the invention is the provision of a pneumatic control means that operates against a compensating means and that responds to a pressure, as determined by proximity of the reading heads to a surface such as the surface 10.

The numeral 60 refers to a spring compressed between the standard 34 of the base and the carrier 36 to urge the nozzle away from the surface 10 when the pneumatic device is not operating. The spring is of relatively light tension and does not affect the operation of the bellows when the pressure in the device is up.

In use, the discharge of the nozzles against the side of the drum 10 cause a build up of pressure within the bellows 32 whereby they exert a force against the force of the compensating bellows 36. Compensating bellows 36 have a force as determined by operating line pressure. In the event that the distance between the nozzles and hence the recording head and the drum 10 should increase for some reason, the pressure in the control bellows 32 would drop because of the more free escape of air from the nozzles 30. The force exerted by the compensating bellows on the carrier, previously in equilibrium with the force of the control bellows is now greater than the force exerted by the control bellows 32 and the compensating bellows move the carrier towards the drum as it expands. This movement carries the nozzle closer to the drum with a resulting build up of pressure in the control bellows 32 due to the decreased distance between the nozzles 30 and the drum. The movement of the compensating bellows will stop when the pressure in the control bellows 32 is again such that the force of the two bellows are in equilibrium and the distance between the nozzle and the drum is maintained as predetermined.

It will be apperent that the predetermined distance can be adjusted by adjusting the force of the compensating bellows 36.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. For a computer having a base, a storage drum on said base and a plurality of reading and/or writing heads mounted in proximity to the recording surface of said drum, an improved mounting for said reading and/0r writing heads comprising a carrier for said heads adjustably mounted with respect to said base to support said heads in various degrees of proximity to the recording surface of said drum, pneumatic control means connected to said base and to said carrier, said pneumatic control means including a control nozzle mounted on said carrier to discharge against a surface of said drum whereby the pressure in said nozzle is a function of the distance between said nozzle and said drum surface, compensating means connecting with said base and with said carrier to exert a constant predetermined force on said carrier in the direction of said drum surface, said control means being responsive to pressure in said nozzle to exert a force on said carrier in a direction away from said drum surface, the force of said compensating means on said carrier being adapted to oppose the force of said control means on said carrier and to balance the force of said control means when said nozzle is a predetermined distance from said recording surface of said drum whereby the correct degree of .proximity between heads carried by said carrier and said drum is maintained, said control means including a control bellows responsive to nozzle pressure and connecting with said base and with said carrier.

2. For a computer having a base, a storage drum on said base and a plurality of reading and/ or writing heads mounted in proximity to the recording surface of said drum, an improved mounting for said reading and/or 'writing heads comprising a carrier for said heads adjustably mounted with respect to said base to support said ends in various degrees of proximity to the recording surface of said drum, pneumatic control means connected to said base and to said carrier, said pneumatic control means including a control nozzle mounted on said carrier to discharge against a surface of said drum whereby th pressure in said nozzle is a function of the distance between said nozzle and said drum surface, compensating means connecting with said base and with said carrier to exert a constant predetermined force on said carrier in the direction of said drum surface, said control means being responsive to pressure in said nozzle to exert a force on said carrier in a direction away from said drum surface, the force of said compensating means on said carrier being adapted to oppose the force of said control means on said carrier and to balance the force of said control means when said nozzle is a predetermined distance from said recording surface of said drum whereby the correct degree of proximity between heads carried by said carrier and said drum is maintained, said compensating means including a bellows connecting with said base and with said carrier.

3. For a computer having a base, a storage drum on said base and a plurality of reading and/ or writing heads mounted in proximity to the recording surface of said drum, an improved mounting for said reading and/ or writing heads comprising a carrier for said heads adjustably mounted with respect to said base to support said heads in various degrees of proximity to the recording surface of said drum, pneumatic control means connected to said base and to said carrier, said pneumatic control means including a control nozzle mounted on said carrier to discharge against a surface of said drum whereby the pressure in said nozzle is a function of the distance between said nozzle and said drum surface, compensating means connecting with said base and with said carrier to exert a constant predetermined force on said carrier in the direction of said drum surface, said control means being responsive to pressure in said nozzle to exert a force on said carrier in a direction away from said drum surface, the force of said compensating means on said carrier being adapted to oppose the force of said control means on said carrier and to balance the force of said control means when said nozzle is a predetermined distance from said recording surface of said drum whereby the correct degree of proximity between heads carried by said carrier and said drum is maintained, said mounting having supply means for supplying an operating gas to said pneumatic control means said supply having a high resistance to gas flow relative to the resistance to gas flow of said nozzle and second supply means for supplying an operating gas to said compensating means, said second supply means having a high impedance to prevent sudden build up or let down of pressure in said bellows.

4. For a computer having a base, a storage drum on said base and a plurality of reading and/ or writing heads mounted in proximity to the recording surface of said drum, and improved mounting for said reading and/ or writing heads comprising a carrier for said heads adjustably mounted with respect to said base to support said heads in various degrees of proximity to the recording surface of said drum, pneumatic control means connected to said base and to said carrier, said penumatic control means including a control nozzle mounted on said carrier to discharge against a surface of said drum whereby the pressure in said nozzle is a function of the distance between said nozzle and said drum surface, compensating means connecting with said base and with said carrier to exert a constant predetermined force on said carrier in the direction of said drum surface, said control means being responsive to pressure in said nozzle to exert a force on said carrier in a direction away from said drum surface, the force of said compensating means on said carrier being adapted to oppose the force of said control means on said carrier and to balance the force of said control means when said nozzle is a predetermined distance from said recording surface of said drum whereby the correct degree of proximity between heads carried by said carrier and control means that has a high resistance to gas flow rela- 1 tive to the resistance to gas flow of said nozzle.

'7. A mounting as claimed in claim 2 in which the means for supplying an operating gas to said pneumatic control means has a high resistance to gas flow relative to the resistance to gas flow of said nozzle and the means for supplying an operating gas to said compensating bellows has a high impedance to prevent sudden build-up or let-down of pressure in said bellows.

8. A mounting as claimed in claim 1 in which said control means has a plurality of nozzles spaced apart on said carrier.

References Cited in the file of this patent UNITED STATES PATENTS 2,441,044 Tate May 4, 1948 2,905,768 Cronquist Sept. 22, 1959 2,928,709 Baumeister Mar. 15, 1960 2,937,240 Harker May 17, 1960 2,949,123 Lawrence Aug. 16,1960

FOREIGN PATENTS 1,020,803 Germany Dec. 12, 1957 

1. FOR A COMPUTER HAVING A BASE, A STORAGE DRUM ON SAID BASE AND A PLURALITY OF READING AND/OR WRITING HEADS MOUNTED IN PROXIMITY TO THE RECORDING SURFACE OF SAID DRUM, AN IMPROVED MOUNTING FOR SAID READING AND/OR WRITING HEADS COMPRISING A CARRIER FOR SAID HEADS ADJUSTABLY MOUNTED WITH RESPECT TO SAID BASE TO SUPPORT SAID HEADS IN VARIOUS DEGREES OF PROXIMITY TO THE RECORDING SURFACE OF SAID DRUM, PNEUMATIC CONTROL MEANS CONNECTED TO SAID BASE AND TO SAID CARRIER, SAID PNEUMATIC CONTROL MEANS INCLUDING A CONTROL NOZZLE MOUNTED ON SAID CARRIER TO DISCHARGE AGAINST A SURFACE OF SAID DRUM WHEREBY THE PRESSURE IN SAID NOZZLE IS A FUNCTION OF THE DISTANCE BETWEEN SAID NOZZLE AND SAID DRUM SURFACE, COMPENSATING MEANS CONNECTING WITH SAID BASE AND WITH SAID CARRIER TO EXERT A CONSTANT PREDETERMINED FORCE ON SAID CARRIER IN THE DIRECTION OF SAID DRUM SURFACE, SAID CONTROL MEANS BEING RESPONSIVE TO PRESSURE IN SAID NOZZLE TO EXERT A FORCE ON SAID CARRIER IN A DIRECTION AWAY FROM SAID DRUM SURFACE, THE FORCE OF SAID COMPENSATING MEANS ON SAID CARRIER BEING ADAPTED TO OPPOSE THE FORCE OF SAID CONTROL MEANS ON SAID CARRIER AND TO BALANCE THE FORCE OF SAID CONTROL MEANS WHEN SAID NOZZLE IS A PREDETERMINED DISTANCE FROM SAID RECORDING SURFACE OF SAID DRUM WHEREBY THE CORRECT DEGREE OF PROXIMITY BETWEEN HEADS CARRIED BY SAID CARRIER AND SAID DRUM IS MAINTAINED, SAID CONTROL MEANS INCLUDING A CONTROL BELLOWS RESPONSIVE TO NOZZLE PRESSURE AND CONNECTING WITH SAID BASE AND WITH SAID CARRIER. 